Preparation of a pure autologous biodegradable fibrin matrix for tissue engineering
Parallel to the growing role of tissue engineering, the need for cell embedding materials, which allow cells to stabilise in a three-dimensional distribution, has increased. Although several substances have been tested, fibrin is thus far the only one that permits the clinical application of cultured tissue. To date, autologous fibrinogen has usually been polymerised with bovine thrombin, which can cause severe immunological side effects. The objective of this study was to explore the practicability of obtaining autologous thrombin from a single patient in an adequate concentration and amount. Fibrinogen was cryoprecipitated from 200 ml of freshly-frozen plasma. Thrombin was isolated from the supernatant through ion-exchange chromatography. The thrombin was first bound to Sephadex A-50 and then eluated using 2 ml of a salt buffer (2.0 M NaCl in 0.015 M trisodiumcitrate, pH 7.0). The activity of the thrombin (51 NIH x ml(-1) to 414 NIH x ml(-1) reached levels comparable to those in commercially available fibrin glues (4-500 NIH x ml(-1)). The study has shown that it is possible to obtain a sufficient amount of autologous thrombin from a single donor to create a fibrin matrix of high efficiency without the risk of immunological and infectious side effects.
[Show abstract] [Hide abstract] ABSTRACT: Dacron® (polyethylene terephthalate) and Goretex® (expanded polytetrafluoroethylene) vascular grafts have been very successful in replacing obstructed blood vessels of large and medium diameters. However, as diameters decrease below 6 mm, these grafts are clearly outperformed by transposed autologous veins and, particularly, arteries. With approximately 8 million individuals with peripheral arterial disease, over 500,000 patients diagnosed with end-stage renal disease, and over 250,000 patients per year undergoing coronary bypass in the USA alone, there is a critical clinical need for a functional small-diameter conduit [Lloyd-Jones et al., Circulation 2010;121:e46-e215]. Over the last decade, we have witnessed a dramatic paradigm shift in cardiovascular tissue engineering that has driven the field away from biomaterial-focused approaches and towards more biology-driven strategies. In this article, we review the preclinical and clinical efforts in the quest for a tissue-engineered blood vessel that is free of permanent synthetic scaffolds but has the mechanical strength to become a successful arterial graft. Special emphasis is given to the tissue engineering by self-assembly (TESA) approach, which has been the only one to reach clinical trials for applications under arterial pressure.0Comments 62Citations
- "As an alternative to collagen scaffolds, a number of groups have also researched the use of cell-impregnated fibrin gels to create vascular grafts. While most studies have been performed with isolated/processed components , a possible advantage of using fibrin is that fibrinogen and thrombin, the precursors to fibrin gel formation, can be readily obtained from a patient's own blood [Haisch et al., 2000] . Like collagen gel-based grafts, constructs created from fibrin-gels have a typically low mechanical strength. "
[Show abstract] [Hide abstract] ABSTRACT: Our objective was to examine the potential of a genipin cross-linked human fibrin hydrogel system as a scaffold for articular cartilage tissue engineering. Human articular chondrocytes were incorporated into modified human fibrin gels and evaluated for mechanical properties, cell viability, gene expression, extracellular matrix production and subcutaneous biodegradation. Genipin, a naturally occurring compound used in the treatment of inflammation, was used as a cross-linker. Genipin cross-linking did not significantly affect cell viability, but significantly increased the dynamic compression and shear moduli of the hydrogel. The ratio of the change in collagen II versus collagen I expression increased more than 8-fold over 5 weeks as detected with real-time RT-PCR. Accumulation of collagen II and aggrecan in hydrogel extracellular matrix was observed after 5 weeks in cell culture. Overall, our results indicate that genipin appeared to inhibit the inflammatory reaction observed 3 weeks after subcutaneous implantation of the fibrin into rats. Therefore, genipin cross-linked fibrin hydrogels can be used as cell-compatible tissue engineering scaffolds for articular cartilage regeneration, for utility in autologous treatments that eliminate the risk of tissue rejection and viral infection.0Comments 36Citations
- "Nevertheless , we have shown that the human fibrin gel system offers a potential patient-specific autologous scaffold for cartilage regeneration, since human fibrinogen and thrombin can be isolated separately from a patient's fresh plasma, and encapsulated cells can be donated by the same patient [Rock et al., 2001] . The advantage of a completely autologous approach for gel formation would be the elimination of the risk of tissue incompatibility and viral infection [Haisch et al., 2000] as well as an associated ease of transition to clinical use. "
[Show abstract] [Hide abstract] ABSTRACT: Articular cartilage is a challenging tissue to reconstruct or replace principally because of its avascular nature; large chondral lesions in the tissue do not spontaneously heal. Where lesions do penetrate the bony subchondral plate, formation of hematomas and the migration of mesenchymal stem cells provide an inferior and transient fibrocartilagenous replacement for hyaline cartilage. To circumvent the poor intrinsic reparative response of articular cartilage several surgical techniques based on tissue transplantation have emerged. One characteristic shared by intrinsic reparative processes and the new surgical therapies is an apparent lack of lateral integration of repair or graft tissue with the host cartilage that can lead to poor prognosis. Many factors have been cited as impeding cartilage:cartilage integration including; chondrocyte cell death, chondrocyte dedifferentiation, the nature of the collagenous and proteoglycan networks that constitute the extracellular matrix, the type of biomaterial scaffold employed in repair and the origin of the cells used to repopulate the defect or lesion. This review addresses the principal intrinsic and extrinsic factors that impede integration and describe how manipulation of these factors using a host of strategies can positively influence cartilage integration.0Comments 90Citations
- "Each successive iteration in scaffold design has attempted to optimise biocompatibility, porosity, bioresorption, biomechanical strength, cell retention and integration (generally in the vertical dimension) to maximise repair with the major emphasis on defect filling and hyaline cartilage production. The assumption that natural substances such as fibrin, collagen or hyaluronan provide superior templates for cartilage repair of defects is unfounded: they too can be subject to inflammatory or degradative responses (Haisch et al., 2000; Knudson et al., 2000), although the use of autologous biomaterials such as plasma-derived fibrin can negate this effect (Munirah et al., 2007). Even collagen-based scaffolds produce incongruities in lateral integration in experimental animal studies of osteochondral repair (Wakitani et al., 1994). "